Melbourne - South African pair Branden Grace and George Coetzee have flopped on Day 1 of the ISPS Handa World Cup of Golf at Royal Melbourne.
Grace posted a two-over par round of 74, while Coetzee faired one shot worse as South Africa found themselves in a tie for 16th, some 11 strokes behind the early leaders, the USA and Denmark.
American Kevin Streelman bogeyed two of his last three holes to fall back into a share of a one-stroke lead with Denmark's Thomas Bjorn after the first round of the $8 million tournament on Thursday, as the headline acts toiled Down Under.
Streelman, a late choice to represent the defending champion United States team, had torn up Royal Melbourne's back nine with five birdies in six holes but dropped shots on the tricky 16th and 18th to card a 66 and join Bjorn on five-under.
The pair finished a stroke ahead of Welshman Stuart Manley, South Korea's K.J. Choi and Scotland's Martin Laird.
"I was very pleased with that start," the 35-year-old Streelman told reporters after upstaging world number seven compatriot Matt Kuchar (71), who won the last World Cup for the US with Gary Woodland in 2011 when it was purely a team event.
"It's just an incredible golf course, I love it... I just had a lot of fun there to be honest."
The tournament's format has been changed from being solely a team event to primarily an individual one with a team component.
Sixty players are competing for individual honours while 26 two-player teams are competing for the team prize.
Having given themselves every chance of winning the individual trophy, Streelman and European Tour journeyman Bjorn also put their nations in the box seat for team honours.
Streelman and Kuchar's combined score of five-under left the United States level with Denmark's Bjorn and Thorbjorn Olesen (71), three strokes ahead of Portugal's Jose-Filipa Lima (71) and Ricardo Santos (69).
Along with fluky gusts of wind, the flint-hard greens at the famed sandbelt course conspired to leave most of the favourites grinding through bogey-strewn back nines, but only one disastrous hole was needed to leave local hero Adam Scott all but out of contention.
The world number two had grafted patiently to one-under at the turn but racked up a quintuple-bogey nine at the par-four 12th after putting two tee-shots into a tangle of scrub and losing his first ball.
The 33-year-old put his third tee-shot into light rough before over-cooking his approach and ended up missing a 12-foot putt for eight to post his worst single-hole score in a PGA Tour event for six years.
Scott never recovered, finishing four-over, but there was some cheer for local fans as his compatriot Jason Day shot a solid 68 to be two off the pace, alone on three-under.
Day, grieving the loss of eight relatives in the Philippines who were killed in Typhoon Haiyan, rolled in five birdies and two bogeys in his first round in five weeks.
Former major winner Graeme McDowell, playing for Ireland, was another of the tournament's contenders to struggle and finished with a one-over 72.
McDowell enjoyed one of the shots of the day, holing a long-range chip for an eagle on the par-four ninth, but stumbled with double-bogeys on the sixth and 18th.
Leading first-round completed scores on Thursday at the ISPS Handa World Cup of Golf at Royal Melbourne (Par 71):
Kevin Streelman (USA) 66
Thomas Bjorn (DAN) 66
Stuart Manley (WAL) 67
K J Choi (KOR) 67
Martin Laird (SCO) 67
Jason Day (AUS) 68
Ricardo Santos (POR) 69
Danny Willett (ENG) 69
Tony Lascuna (PHI) 70
Mikko Korhonen (FIN) 70
Nicolas Colsaerts (BEL) 70
David Hearn (CAN) 70
Brad Fritsch (CAN) 71
Jose-Filipe Lima (POR) 71
Kiradech Aphibarnrat (THA) 71
Ryo Ishikawa (JAP) 71
Thorbjorn Olesen (DAN) 71
Bernd Weisberger (AUT) 71
Matt Kuchar (USA)71
Marcel Siem (GER) 71
Graeme McDowell (NIR) 72
Vijay Singh (FIJ) 73
Adam Scott (AUS) 75
USA (Streelman/Kuchar) 66/71 137
Denmark (Bjorn/Olesen) 66/71 137
Portugal (Santos/Lima) 69/71 140
South Korea (Choi/Bae) 67/74 141
Scotland (Laird/Gallacher) 67/74 141
Canada (Hearn/Fritsch) 70/71 141
Finland (Korhonen/Kakko) 70/72 142
Thailand (Aphibarnrat/Marksaeng) 71/72 143
Japan (Ishikawa/Tanihara) 71/72 143
Australia (Day/Scott) 68/75 143
Germany (Siem/Keiffer) 71/73 144
Philippines (Lascuna/Que) 70/74 144
England (Willett/Wood) 69/75 144
Brazil (Da Silva/Rocha) 72/72 144
France (Dubuisson/Bourdy) 73/72 145
Ireland (McDowell/Lowry) 72/75 147
South Africa (Grace/Coetzee) 73/75 148
Italy (F Molinari/Manassero) 75/76 151